[bash] indirect array reference to array with values containing spaces

Meson · 06-04-2010, 11:03 AM

This _almost_ works. I just can't quite get it to honor the spaces.

Code:

#!/bin/bash

profiles=(
        PROFILE_ONE
)

PROFILE_ONE=(setting1 "setting number 2")

for p in "${profiles[@]}"; do

        echo "original p:         ${p}"

        eval p=(\${${p}[@]})

        echo "new p:              ${p}"
        echo "new p contents:     ${p[@]}"

        echo "new p split:"

        for o in "${p[@]}"; do
                echo "                    $o"
        done
done

echo
echo

rweaver · 06-04-2010, 11:21 AM

You could use IFS to do this... http://tldp.org/LDP/abs/html/internalvariables.html (Note change to PROFILE_ONE)

Code:

#!/bin/bash
IFS_ORIG=$IFS
IFS=","
profiles=(
        PROFILE_ONE
)

PROFILE_ONE=(setting1, "setting number 2")

for p in "${profiles[@]}"; do

        echo "original p:         ${p}"

        eval p=(\${${p}[@]})

        echo "new p:              ${p}"
        echo "new p contents:     ${p[@]}"

        echo "new p split:"

        for o in "${p[@]}"; do
                echo "                    $o"
        done
done

echo
echo
IFS=$IFS_ORIG

Meson · 06-04-2010, 12:43 PM

Thanks,

One oddity about this though, is that newlines still work as a separator. Can anyone explain this?

Just for anyone coming across this, you only need to change the IFS when going over the loop. Also you need to check for some blank entries:

Code:

#!/bin/bash

profiles=(
        PROFILE_ONE
)

PROFILE_ONE=(setting1, "setting number 2")

IFS_ORIG=$IFS
IFS=","
for p in "${profiles[@]}"; do

        echo "original p:         ${p}"

        eval p=(\${${p}[@]})

        echo "new p:              ${p}"
        echo "new p contents:     ${p[@]}"

        echo "new p split:"

        for o in "${p[@]}"; do
                [ "$o" == "" ] && continue
                echo "                    $o"
        done
done
IFS=$IFS_ORIG

echo
echo

Meson · 06-04-2010, 01:01 PM

Actually, I still have a problem with this. It has to do with quoted strings:

Code:

#!/bin/bash

profiles=(
        PROFILE_ONE
)

PROFILE_ONE=(
        setting1,
        "setting number 2",
        \"setting number 3\"
)

IFS_ORIG=$IFS
IFS=","
for p in "${profiles[@]}"; do

        echo "original p:         ${p}"

        eval p=(\${${p}[@]})

        echo "new p:              ${p}"
        echo "new p contents:     ${p[@]}"

        echo "new p split:"

        for o in "${p[@]}"; do
                [ "$o" == "" ] && continue
                echo "                    $o"
        done
done
IFS=$IFS_ORIG

echo
echo

Here, setting 2 id displayed as an atom without quotes, setting 3 is displayed as 3 atoms, the first one leading with a quote and the third one trailing with a quote.

catkin · 06-04-2010, 01:02 PM

The code can be tightened up a little like this, assuming IFS starts with the default value (and legibility is not a prime concern!)

Code:

#!/bin/bash

profiles=(
        PROFILE_ONE
)

PROFILE_ONE=(setting1, "setting number 2")

#IFS_ORIG=$IFS
IFS=","
for p in "${profiles[@]}"; do

        echo "original p:         ${p}"

        eval p=(\${${p}[@]})

        echo "new p:              ${p}"
        echo "new p contents:     ${p[@]}"

        echo "new p split:"

        for o in "${p[@]}"; do
                # [ "$o" == "" ] && continue
                [ "$o" == "" ] || echo "                    $o"
        done
done
#IFS=$IFS_ORIG
unset IFS

Note: If IFS is unset bash behaves in all respects as if it had the default value.

catkin · 06-04-2010, 01:06 PM

Quote:

Originally Posted by Meson

Actually, I still have a problem with this.
...
Here, setting 2 id displayed as an atom without quotes, setting 3 is displayed as 3 atoms, the first one leading with a quote and the third one trailing with a quote.

Why is that a problem? PROFILE_ONE as initialised is a five element array. AIUI the described display is correct ... ???

Meson · 06-04-2010, 01:42 PM

The example above displays as:

Code:

setting1
setting number 2
"setting
number
3"

This is not what I want. It should be:

Code:

setting1
setting number 2
"setting number 3"

catkin · 06-04-2010, 01:45 PM

But that is not the content of PROFILE_ONE when it is initialised with

Code:

PROFILE_ONE=(
        setting1,
        "setting number 2",
        \"setting number 3\"
)

Meson · 06-04-2010, 02:02 PM

I don't know what you mean by that. If I set IFS=, then I expect for that declaration of PROFILE_ONE to have 3 items, not 5.

catkin · 06-04-2010, 09:38 PM

Hadn't the IFS=, been moved after the array initialisation? And anyway setting IFS=, and then using "," as an array element separator doesn't work:

Code:

c@CW8:~$ IFS=,
c@CW8:~$ x=(a, b,c)
c@CW8:~$ echo "'${x[0]}'"
'a,'
c@CW8:~$ echo "'${x[1]}'"
'b,c'